Trim attachment for power boats



Nov. 6, 1962 c. H. BENNETT TRIM ATTACHMENT FOR POWER BOATS 2 Sheets-Sheet 1 Filed April 27, 1961 INVENTOR.

C/l/QRZEJ f7. If/V/VETT Nov. 6, 1962 .c. H. BENNETT TRIM ATTACHMENT FOR POWER BOATS 2 Sheets-Sheet 2 Filed April 27, 1961 INVEN TOR.

094A: is A! ai/wvirr A TTORIVAYS' United rates atent 3,062,167 Patented Nov. 6, 1962 ice This invention relates to boating and particularly to power boats.

It has long been known that variation in loading due to fuel, water and passengers causes a power boat to assume an attitude which may not be the best and most efiicient for movement through the water at the highest speed and greatest engine efficiency.

It has heretofore been suggested that fixed surfaces or shingles be provided on the underside of the boat which assist the boat in moving through the water at a proper attitude under a particular loading. However, such fixed surfaces have the disadvantage that they are only applicable to a particular loading and have the further disadvantage that they make the boat very unworthy in a following sea, that is, where the wind is blowing the same way that the boat is traveling. In a following sea, when a boat is lightly loaded and equipped with such shingles, the boat is likely to broach or be pitched to one side when a large wave gets under and picks up the stern of the boat. -It has also been suggested that rigid adjustable shingles be provided. However, such shingles have not been found to be effective with power boats of the type wherein the bottom planking is not flat, that is, wherein the keel line tapers upwardly relative to the chine line at the stern of the boat.

Accordingly, it is an object of this invention to provide a trim attachment for power boats having a keel line tapered upwardly relative to the chine line which permits longitudinal and lateral trimming of the boat under varying loading in order to obtain optimum attitude for movement of the boat through the water, greater speed with less fuel consumption, improved visibility and permitting adjustment so that the compensation can be made for varying load conditions and can be removed in rough waters.

3 In the drawings: 2 FIG. 1 is a side elevation of a power boat embodying the invention.

FIG. 2 is a fragmentary perspective view of the stern of the power boat shown in FIG. 1.

FIG. 3 is a sectional view taken along the line 3-3 in FIG. 2.

1 FIG. 4 is a sectional view taken along the line 4-4 in FIG. 3.

FIG. 5 is a sectional view taken along the line 5-5 in FIG. 4.

FIG. 6 is a fragmentary end view of the attachment shown in FIG. 3.

FIG. 7 is a sectional view taken along the line 7-7 in FIG. 3.

FIG. 8 is a fragmentary view similar to FIG. 3 showing a modified form of the apparatus.

FIG. 9 is a sectional view taken along the line 99 in FIG. 8.

FIG. 10 is a fragmentary view similar to FIG. 3 showing a further modified form of the apparatus.

Referring to FIG. 1, the invention is adapted to be applied to a power boat 10 of the type wherein the bottom planking is not flat, that is which has a keel 11 that tapers upwardly toward the stern 12 of the boat and a chine line 13 that tapers generally horizontally and downwardly relative to the keel 11 at the stern 12. Such a boat comprises a transom 14 at the stern which is usually inclined upwardly and rearwardly.

,, As shown in FIG. 2, according to the invention, a pair of attachments 15 are provided on the transom 14 on each side of the center or keel line 11.

Each trim attachment 15 comprises a trim member or tab 16 (FIG. 3) which is made of generally uniformly thick material that is flexible, as presently described.

7 Each tab 16 is generally rectangular and flat and is hinged along its forward edge by a piano hinge 17 to the transom 14 at the junction of the transom with the undersurface 18 of the boat. Hinge 17 is formed by the forward edge of tab 16 and the lower edge of a plate 17 fixed to the transom 14. Each trim tab 16 includes an upwardly turned portion 19 at the rear edge thereof so that a substantially flat undersurface 20 is provided between the front and rear edge of the tab. Hinge 17 is positioned in such a manner that the surface 20 is substantially coplanar to the edge forming the area of juncture between the transom 14 and undersurface 18.

Each trim tab 16 is adapted to be individually moved downwardly to a position inclined downwardly with respect to the horizontal, as shown in dotted lines in FIG. 3,

by a suitable operating mechanism that comprises an inverted V-shaped link 22 that is made of a bent rod and includes arms 23, 24. Arm 23 extends through an opening in the portion 20 of trim member 16 adjacent the center portion thereof and near the hinge 17 and is fixed thereto by nuts 25. Arm 24 is pivoted to upwardly turned portion 19 intermediate its end. Specifically, the end 26 of arm 24 extends forwardly through an opening in portion 19 and is pivoted thereto by cotter pins 27-, 28. The arms 23, 24 of link 22 lie in a plane I that is substantially parallel to a longitudinal plane ofthe boat and at a right angle to the axis of hinge 17.

' Each member 22 is moved forwardly and rearwardly and thereby pivots its respective trim tab 16 by a mechanism which includes a shaft 29 that is clamped to arm 23 and is slidable through an opening 30 in the transom 14. Shaft 29 has a screw 31 on the inner end thereof. Screw 31 meshes with a pinion 32 of an electric motor 33 fixed to a support 34 within the boat. When the electric motor 33 is operated, the shaft 29 is translated inwardly or outwardly to swing the trim tab 16 up or down. As is shown in FIG. 5, a plastic grommet 35 surrounds the shaft 30 and is held in position by a plastic collar 36 to form a seal against the entry of water within the boat. Grommet 35 moves vertically with shaft 30. Collar 36 is formed with a vertically elongated opening through which shaft 30 extends. The piano hinge 17 prevents water from readily extending upwardly above the trim tab 16.

The tab is made of a uniformly thick material that is flexible, such as stainless steel sheet of about 12 to 14 gauge. As shown in FIG. 7 which is a view of the trim attachment on the port side of the boat, when the trim tab is extended downwardly below the horizontal and the boat is driven through the water, the inherent flexibility of the material of the trim member permits it to flex so that the tab conforms with the curvature of the bottom planking or surface at the stern. The left-hand portion of the tab tends to follow the contour of the chine line, namely, tapered downwardly, while the righthand portion tends to follow the taper of the keel line, namely, tapering upwardly. On the starboard side of the boat, the trim tab 16 would be flexed in the opposite manner to conform to the bottom surface.

I have found that the maximum adjustment of each trim tab required for all conditions is 10 degrees below the horizontal.

Tests utilizing the trim tabs show that the trim tabs not only trim the boat longitudinally but, in addition, laterally to compensate for variations in load placing the boat in the proper attitude for maximum speed and mini- 3 g mum fuel consumption. By properly trimming the boat, it is possible to obtain increased visibility. In addition, since the trim can be removed by moving the trim tabs to horizontal position, maximum safety is achieved in a following sea so that there is no danger of broaching the boat.

The trim tabs are relatively inexpensive and can be applied with a minimum of effort. Since the power mechanism is fixed within the boat, a minimum of strain is applied to the transom.

As shown in FIG. 1, it is preferred that the rear edges of the trim tab 16 lie within a vertical plane extending downwardly from the upper edge of.the transom so that no damage will be encountered in cases of backing up the boat against piling and the like.

A typical test of a 28 foot power boat on a measured mile with predetermined load and predetermined throttle setting was as follows:

A modified form of apparatus is shown in FIGS. 8 and 9 and includes a bracket 40 having a flange through which the lower end of arm 24 extends. Bracket 40 is vertically adjustable on the arm by nuts 41 threaded on the arm 24 on each side of the one flange of the bracket 40. The other flange of the bracket 40 is pivoted to upwardly turned portion 19 by a bolt 42. By this arrangement, the zero or neutral position of the trim tab 16 can be adjusted, that is, with the shaft 30 in a predetermined position, the trim tab 16 can be adjusted up or down.

A further modified form of the invention is shown in FIG. 10 wherein the trim tab 16 is made of a single sheet of material having a portion 45 of reduced cross section extending throughout the length thereof. This portion 45 forms a hinge permitting the trim tab 16' to swing relative to the transom 14 sufliciently to provide the angular displacement necessary for operation of the trim tab.

Although the trim tabs in the drawings have been shown as applied to a transom that is substantially flat, it is within the scope of the invention to apply the trim tabs to transoms that are curved relative to the boat. In such a case, provision must be made to support the substantially straight hinge formed by the piano hinge in FIGS. 3 and 8 and by the portion of reduced thickness in FIG. 10. This can be achieved by causing plate 17' to be curved and conform to the transom 14 and providing a flat horizontal extension at the lower edge of the plate 17 which extends rearwardly to the straight hinge.

Although the plate comprising the trim tab has been described as substantially flat, it can be appreciated that the plate could have ribs therein which provide rigidity in a longitudinal direction with respect to the boat but permit the flexing or bending in a lateral direction so that the tab can assume the configuration shown in FIG. 7.

This application is a continuation-in-part of my copending application Serial No. 81,302, filed January 9, 1961, now abandoned.

I claim:

1. In a power boat having a keel and a chine line wherein the keel tapers upwardly relative to the chine line adjacent the stern of the boat, the combination comprising a pair of trim members hinged to the stern, one on each side of the center line of the boat, each trim member being hinged along its forward edge to the boat in a line lying in the plane of the underside of the boat within the lateral confines of the boat, each trim member having means adjacent the rear edge thereof tending to rigidify the member, each said trim member having a substantially flat undersurface with the forward edge of the member lying substantially in the plane of the underside of the boat, said means tending to rigidify the trim member lying entirely above the undersurface thereof, each said trim member having a portion thereof intermediate the forward and rear edges which is relatively flexible, and power operated means extending between the boat and each said trim member intermediate the side edges and substantially centrally thereof for varying the inclination of said trim member from a position substantially coplanar with the underside of the boat to a position forming a downwardly extending angle with the underside of the boat.

2. In a power boat having a keel and a chine line wherein the keel tapers upwardly relative to the chine line adjacent the stern of the boat, the combination comprising a pair of trim members hinged to the stern, one on each side of the center line of the boat, each trim member being hinged along its forward edge to the boat in a line lying in the plane of the underside of the boat within the lateral confines of the boat, each trim member having means adjacent the rear edge thereof tending to rigidify the member, each said trim member having a substantially fiat undersurface with the forward edge of the member lying substantially in the plane of the underside of the boat, each said trim member having a portion thereof intermediate the forward and rear edges which is relatively flexible, and power operated means extending between the boat and each said trim member intermediate the side edges and substantially centrally thereof for varying the inclination of said trim member from a position substantially coplanar with the underside of the boat to a position forming a downwardly extending angle with the underside of the boat, the means adjacent the rear edge of each said trim member tending to rigidify the member comprising an upwardly turned portion at the rear edge thereof.

3. The combination set forth in claim 2 wherein said power operated means extends between said upwardly turned portion and said boat.

4. The combination set forth in claim 2 wherein said power operated means is connected to said upwardly turned portion and the portion of said trim member intermediate the forward and rear edges.

5. The combination set forth in claim 1 wherein said power operated means includes an inverted V-shaped member having a pair of arms which lie in a plane substantially parallel to the center line of the boat, the lower ends of at least one of said arms being connected respectively to the trim member. said power operated means including a shaft member slidably connected to the upper end of said V-shaped member and adapted to be moved inwardly and outwardly relative to the boat to vary the inclination of said trim member relative to said boat.

6. In a power boat having a keel and a chine line wherein the keel tapers upwardly relative to the chine line adjacent the stern of the boat, the combination comprising a pair of trim members, each said trim member being made of a material having substantially uniform thickness and comprising a forward edge and a rear edge which are generally parallel, means for hinging each said trim member to said boat at the area of juncture of the underside of the boat with the transom of the boat within the lateral confines of the boat, each said trim member having an upwardly turned portion along the rear edge thereof and a substantially flat relatively flexible undersurface extending between the front and rear edge thereof with the forward edge thereof lying substantially in the plane of the underside of the boat, and extensible means pivoted to each of said trim member intermediate the ends and substantially centrally thereof and extending to said transom.

7. The combination set forth in claim 6 wherein said extensible means includes a link fastened to said trim member,. a shaft member fastened to said link extending through the transom and movable inwardly and outwardly relative thereto, means for operatively connecting said shaft member to the link.

8. In a power boat having a keel and a chine line wherein the keel tapers upwardly relative to the chine line adjacent the stern of the boat, the combination comprising a pair of trim members, one on each side of the center line of the boat, each trim member having a portion at its forward edge fixed to the stern and a transversely extending portion of reduced cross section connecting said portion to the trim member and forming a hinge along its forward edge to the boat in a line lying in the plane of the underside of the boat within the lateral confines of the boat, each trim member having means adjacent the rear edge thereof tending to rigidify the member, each said trim member having a substantially flat undersurface with the rear edge of the member lying in the plane of the underside of the boat, said means tending to rigidify the trim member lying entirely above the undersurface thereof, each said trim member having a portion thereof intermediate the forward and rear edges which is relatively flexible, and power operated means extending between the boat and each said trim member intermediate the side edges substantially centrally thereof for varying the inclination of said trim member from a position substantially coplanar with the underside of the boat to a position forming a downwardly extending angle with the underside of the boat.

9. For use in a power boat having a keel and a chine line wherein the keel tapers upwardly relative to the chine line adjacent the stern of the boat, the combination comprising a pair of trim members adapted to be hinged to the stern, one on each side of the center line of the boat, means for hinging each trim member along its forward edge to the boat in a line lying substantially in the plane of the underside of the boat, each trim member having means adjacent the rear edge thereof tending to rigidify the member, each said trim member having a substantially flat undersurface with the rear edge of the member adapted to lie substantially in the plane of the underside of the boat, said means tending to rigidify the trim member lying entirely above the undersurface thereof, each said trim member having a portion thereof intermediate the forward and rear edges which is relatively flexible, and power operated means adapted to extend between the boat and each said trim member intermediate the side edges substantially centrally thereof for varying the inclination of said trim member from a position substantially coplanar with the underside of the boat to a position forming a downwardly extending angle with the underside of the boat.

10. For use in a power boat having a keel and a chine line wherein the keel tapers upwardly relative to the chine line adjacent the stern of the boat, the combination comprising a pair of trim members, each said trim member being made of a material having substantially uniform thickness and comprising a forward edge and a rear edge which are generally parallel, means for hinging each said trim member to a boat at the area of juncture of the underside of the boat with the transom of the boat, each said trim member having an upwardly turned portion along the rear edge thereof and a substantially flat relatively flexible undersurface extending between the front and rear edge thereof with the forward edge thereof adapted to 'be substantially in the plane of the underside of the boat, and extensible means pivoted to each said upwardly turned portion of the trim member intermediate the ends thereof and adapted to extend to said transom.

11. For use in a power boat having a keel and a chine line wherein the keel tapers upwardly relative to the chine line adjacent the stern of the boat, the combination comprising a pair of trim members, each said trim member being made of a material having substantially uniform thickness and comprising a forward edge and a rear edge which are generally parallel, means for hinging each said trim member to a boat at the area of juncture of the underside of the boat with the transom of the boat and forming a water tight hinge, each said trim member having an upwardly turned tab along the rear edge thereof and a substantially flat undersurface extending between the front and rear edge thereof, and extensible means pivoted to each said upwardly turned portion of the trim member intermediate the ends thereof and adapted to extend to said transom, said extensible means comprising an inverted V-shaped link having one arm pivoted to said upwardly turned portion of the trim member about an axis extending longitudinally through said upwardly turned portion.

12. The combination set forth in claim 11 wherein said extensible means include a shaft member fastened to said link adapted to extend through the transom and be movable inwardly and outwardly relative thereto, said shaft member being slidably connected to the other arm of said link and power means adapted to be fixed within the boat and operatively connected to the shaft member for reciprocating the shaft member.

13. In a power boat having a keel and a chine line wherein the keel tapers upwardly relative to the chine line adjacent the stern of the boat, the combination comprising a pair of trim members hinged to the stern, one on each side of the center line of the boat, each trim member being hinged along its forward edge to the boat in a line lying in the plane of the underside of the boat within the lateral confines of the boat, each trim member having means adjacent the rear edge thereof tending to rigidify the member, each said trim member having a substantially flat undersurface with the forward edge of the member lying substantially in the plane of the underside of the boat, said means tending to rigidify the trim member lying entirely above the undersurface thereof, each said trim member having a portion thereof intermediate the forward and rear edges which is relatively flexible, and power operated means extending between the boat and each said trim member intermediate the side edges and substantially centrally thereof for varying the inclination of said trim member from a position substantially coplanar with the underside of the boat to a position forming a downwardly extending angle with the underside of the boat, such that the trim member flex with the inside edges moving upwardly to conform with the keel line and the outer side edges moving downwardly to conform with the chine line.

References Cited in the file of this patent UNITED STATES PATENTS 956,487 Fauber Apr. 26, 1910 978,311 Lake Dec. 13, 1910 1,237,715 Smith Aug. 21, 1917 1,805,131 Donaldson May 12, 1931 1,855,076 Warner Apr. 19, 1932 2,099,492 Luders Nov. 16, 1937 2,576,744 Anderson Nov. 27, 1951 2,807,228 Vandre Sept. 24, 1957 2,985,130 Jacobs et a1. May 23, 1961 3,002,485 Curtis Oct. 3, 1961 FOREIGN PATENTS 80,670 Sweden June 12, 1934 581,736 Great Britain Oct. 23, 1946 

